Fish are good. If you think plain goldfish are boring look at the 'fancy' varieties. Or try the easiest tropical fish. Mollies ( sailfin, potbelly or ordinary) or platies ( hifin, sunset or tuxedo) are livebearers which means they get 'pregnant' & have baby fish instead of laying eggs. Corydorus catfish (6)(albino, bronze, etc.) are very cute & clean up any left over food. Plus one albino ancestrus will eat all your algae without scaring the child to death. All the above live happily together in a 60ltr tank. Get a good book & planning will be as much fun as setting it up. Feed once a day & do a 20% water change once a week. Easy!